The percentage of the world population suffering from morbid obesity is steadily increasing. Severely obese persons are susceptible to increased risk of heart disease, stroke, diabetes, pulmonary disease, and accidents. Because of the effect of morbid obesity to the life of the patient, methods of treating morbid obesity are being researched.
Numerous non-operative therapies for morbid obesity have been tried with virtually no permanent success. Dietary counseling, behavior modification, wiring a patient's jaws shut, and pharmacological methods have all been tried, and though temporarily effective, failed to correct the condition. Further, introducing an object in the stomach, such as an esophago-gastric balloon, to fill the stomach have also been used to treat the condition; however, such approaches tend to cause irritation to the stomach and are not effective long-term.
Surgical treatments of morbid obesity have been increasingly used with greater success. These approaches may be generalized as those that reduce the effective size of the stomach, limiting the amount of food intake, and those that create malabsorption of the food that it is eaten. For instance, some patients benefit from adjustable gastric bands (AGB) that are advantageously laparoscopically placed about the stomach to form a stoma of a desired size that allows food to fill an upper portion of the stomach, causing a feeling of satiety. To allow adjustment of the size of the stoma after implantation, a fluid conduit communicates between an inwardly presented fluid bladder of the AGB to a fluid injection port subcutaneously placed in front of the patient's sternum. A syringe needle may then inject or withdraw fluid as desired to adjust the AGB.
Although an effective approach to obesity for some, other patients may find the lifestyle changes undesirable, necessitated by the restricted amount of food intake. In addition, the medical condition of the patient may suggest the need for a more permanent solution. To that end, surgical approaches have been used to alter the portions of the stomach and/or small intestine available for digesting food. Creating an anastomosis, or the surgical formation of a passage between two normally distinct vessels, is a critical step of many surgical procedures. This is particularly true of gastric bypass procedures in which two portions of small intestine are joined together and another portion of small intestine is joined to the stomach of the patient. This is also true of surgery to alleviate blockage in the common bile duct by draining bile from the duct to the small intestine during surgery for pancreatic cancer.
With particular reference to gastric bypass procedures, current methods of performing a laparoscopic anastomoses for a gastric bypass include stapling, suturing, and placing biofragmentable rings, each having significant challenges. For instance, suturing is time consuming, as well as being technique and dexterity dependent. Stapling requires placement of an anvil, which is a large device that cannot be introduced through a trocar port. Having to introduce the port through a laparotomy presents an increased incidence of wound site infection associated with Intralumenal content being dragged to the laparotomy entry site.
As an example of the latter approach, in U.S. Pat. No. 6,543,456 a method for gastric bypass surgery includes the insertion of proximal and distal anastomosis members (e.g., anvils) transorally with grasping forceps. The stomach and the small intestine are transected endoscopically by a surgical severing and stapling instrument to create a gastric pouch, a drainage loop, and a Roux limb. An endoscopically inserted circular stapler attaches to the distal anastomosis member to join the drainage loop to a distal portion of the intestine, and the circular stapler attaches to the proximal anastomosis member to join the Roux limb to the gastric pouch. Thereafter, the anastomosis members are removed to create an orifice between joined portions of the stomach and intestine. This method reduces the number of laparoscopic ports, avoids a laparoscopic insertion of an anastomosis instrument (e.g., circular stapler) into an enlarged surgical port, and eliminates the need for an enterotomy and an enterotomy closure.
For many anastomoses, surgeons use circular staplers, linear staplers, or manual sutures. However, to reduce incision size and to make the surgical process less technically demanding and time consuming, an anastomotic device that deforms to hold tissue portions together when the device is ejected from a constraining enclosure has been described. Such an approach is described in U.S. patent application Publ. No. US 2003/0032967 and PCT application WO 03/000142 both to Adrian Park et al, which is hereby incorporated herein by reference, describes such a device. Therein, gastrointestinal or enteric (including biliary) anastomosis is achieved by insertion of a sheath that perforates the walls of two tissue passages, such as the stomach and small intestine. A three-dimensional woven tube of wire of having a thermal shape memory effect (SME) (“generally-known nitinol ring device”) is presented by a cannula of the sheath on both sides of the openings. Deployment of the woven tube causes the outer loops or ends of the tube to fold or loop back to hold the luminal interface of the anastomosis site in apposition. Thereby, the need for a mechanical compression component in a delivery system is reduced or avoided, reducing the size and complexity of the delivery device.
The anastomotic device disclosed in WO 03/000142 is constrained by a retractable sheath to an advantageous small-diameter tubular shape. A surgeon applies the anastomotic device by maneuvering the sheath through the tissue portions requiring anastomosis and retracting the sheath. Retracting the sheath removes the constraint on the device, allowing the device to assume a roughly hourglass shape. The larger ends of the hourglass shape hold the two tissue portions together in an effective anastomosis.
The constrained anastomotic device, which may be made of a shape memory material such as nitinol, exerts a force against the inner diameter of the sheath and tends to warp towards its roughly hourglass-shaped deployed position. When the sheath is retracted proximally, the forces generated by the device in transition from a tubular shape to an hourglass shape urge the anastomotic device distally. This device movement makes surgical control harder to achieve when placing the device through the otomies of two tissue portions requiring anastomosis.
While the generally-known nitinol ring device is a significant advancement in the treatment of morbid obesity, it is believed that further improvements would be desirable. For instance, weaving the wire strands and fastening together the ends and heat treating the woven tubes into an SME device is expensive. In addition, it may tend to be difficult to maintain two lumens that are to be anastomotized in extremely close contact in order for the generally-known nitinol ring device to successfully attach to both sides. Having to insert one or more grasping tools along with the anastomosis ring applier tends to mitigate the advantages of a single lumen anastomosis by requiring multiple access ports. Moreover, even if the lumens are proximately position, the generally-known nitinol ring device tends to actuate slowly, if at all, by being limited to SME actuation.
Consequently, there is a general need for an device for single lumen access anastomosis that can be used in existing trocar ports (e.g., 12 mm size) and that reliably and effectively creates an anastomotic attachment between lumens, eliminating the need for surgical stapling and suturing to form an anastomosis.